Hi Dormando, Thanks for the reply, I believe the engine version is 1.5. By multiplier I assumed you meant “chunk_size_growth_factor”, which is currently set at 1.02.
Best, Tony Wu > On Nov 12, 2020, at 2:26 PM, dormando <[email protected]> wrote: > > What version are they running now? That stat output looks pretty sparse. > > Unfortunately when it comes to elasticache the answer is probably to just > beg them to upgrade to a newer version. they tend to run really old and > newer verisons do a lot better at balancing memory. > > This is also suspect: >> STAT 62:chunk_size 712 >> STAT 62:total_chunks 4416 >> STAT 62:free_chunks 631 >> STAT 62:free_chunks_end 0 >> STAT 63:chunk_size 524288 > > anything you store that's larger than 712 bytes will use half a megabyte > of memory. If you're setting the slab multiplier (-f) to something really > aggressive, you should stop that :) > > On Thu, 12 Nov 2020, Tony Wu wrote: > >> We are currently using memcached provided by AWS ElastiCache service in >> modern mode to store web session keys >> among other things. We are observing session keys being evicted before TTL >> even though the cluster seems to have >> ample free memory, which hints at slab imbalance. I've included a print out >> of slab stats below in terms of >> sizing and total / free pages. >> What would be the best way to smooth out this imbalance? We already enabled >> slab reassign / auto-move under >> modern mode. >> >> Thanks. >> >> STAT 1:chunk_size 96 >> STAT 1:total_chunks 131064 >> STAT 1:free_chunks 1664 >> STAT 1:free_chunks_end 0 >> STAT 2:chunk_size 104 >> STAT 2:total_chunks 60492 >> STAT 2:free_chunks 5327 >> STAT 2:free_chunks_end 0 >> STAT 3:chunk_size 112 >> STAT 3:total_chunks 46810 >> STAT 3:free_chunks 79 >> STAT 3:free_chunks_end 0 >> STAT 4:chunk_size 120 >> STAT 4:total_chunks 26214 >> STAT 4:free_chunks 48 >> STAT 4:free_chunks_end 0 >> STAT 5:chunk_size 128 >> STAT 5:total_chunks 32768 >> STAT 5:free_chunks 6193 >> STAT 5:free_chunks_end 0 >> STAT 6:chunk_size 136 >> STAT 6:total_chunks 23130 >> STAT 6:free_chunks 4594 >> STAT 6:free_chunks_end 0 >> STAT 7:chunk_size 144 >> STAT 7:total_chunks 7281 >> STAT 7:free_chunks 5894 >> STAT 7:free_chunks_end 0 >> STAT 8:chunk_size 152 >> STAT 8:total_chunks 13796 >> STAT 8:free_chunks 12008 >> STAT 8:free_chunks_end 0 >> STAT 9:chunk_size 160 >> STAT 9:total_chunks 6553 >> STAT 9:free_chunks 6316 >> STAT 9:free_chunks_end 0 >> STAT 10:chunk_size 168 >> STAT 10:total_chunks 6241 >> STAT 10:free_chunks 6186 >> STAT 10:free_chunks_end 0 >> STAT 11:chunk_size 176 >> STAT 11:total_chunks 5957 >> STAT 11:free_chunks 5946 >> STAT 11:free_chunks_end 0 >> STAT 12:chunk_size 184 >> STAT 12:total_chunks 5698 >> STAT 12:free_chunks 5664 >> STAT 12:free_chunks_end 0 >> STAT 13:chunk_size 192 >> STAT 13:total_chunks 5461 >> STAT 13:free_chunks 5380 >> STAT 13:free_chunks_end 0 >> STAT 14:chunk_size 200 >> STAT 14:total_chunks 5242 >> STAT 14:free_chunks 5135 >> STAT 14:free_chunks_end 0 >> STAT 15:chunk_size 208 >> STAT 15:total_chunks 5041 >> STAT 15:free_chunks 4892 >> STAT 15:free_chunks_end 0 >> STAT 16:chunk_size 216 >> STAT 16:total_chunks 4854 >> STAT 16:free_chunks 4770 >> STAT 16:free_chunks_end 0 >> STAT 17:chunk_size 224 >> STAT 17:total_chunks 4681 >> STAT 17:free_chunks 4655 >> STAT 17:free_chunks_end 0 >> STAT 18:chunk_size 232 >> STAT 18:total_chunks 4519 >> STAT 18:free_chunks 4489 >> STAT 18:free_chunks_end 0 >> STAT 19:chunk_size 240 >> STAT 19:total_chunks 4369 >> STAT 19:free_chunks 4345 >> STAT 19:free_chunks_end 0 >> STAT 20:chunk_size 248 >> STAT 20:total_chunks 4228 >> STAT 20:free_chunks 4217 >> STAT 20:free_chunks_end 0 >> STAT 21:chunk_size 256 >> STAT 21:total_chunks 4096 >> STAT 21:free_chunks 4091 >> STAT 21:free_chunks_end 0 >> STAT 22:chunk_size 264 >> STAT 22:total_chunks 3971 >> STAT 22:free_chunks 3966 >> STAT 22:free_chunks_end 0 >> STAT 23:chunk_size 272 >> STAT 23:total_chunks 3855 >> STAT 23:free_chunks 3851 >> STAT 23:free_chunks_end 0 >> STAT 24:chunk_size 280 >> STAT 24:total_chunks 3744 >> STAT 24:free_chunks 3738 >> STAT 24:free_chunks_end 0 >> STAT 25:chunk_size 288 >> STAT 25:total_chunks 3640 >> STAT 25:free_chunks 3638 >> STAT 25:free_chunks_end 0 >> STAT 26:chunk_size 296 >> STAT 26:total_chunks 3542 >> STAT 26:free_chunks 3533 >> STAT 26:free_chunks_end 0 >> STAT 27:chunk_size 304 >> STAT 27:total_chunks 3449 >> STAT 27:free_chunks 3448 >> STAT 27:free_chunks_end 0 >> STAT 28:chunk_size 312 >> STAT 28:total_chunks 3360 >> STAT 28:free_chunks 3350 >> STAT 28:free_chunks_end 0 >> STAT 29:chunk_size 320 >> STAT 29:total_chunks 3276 >> STAT 29:free_chunks 3273 >> STAT 29:free_chunks_end 0 >> STAT 30:chunk_size 328 >> STAT 30:total_chunks 3196 >> STAT 30:free_chunks 3174 >> STAT 30:free_chunks_end 0 >> STAT 31:chunk_size 336 >> STAT 31:total_chunks 3120 >> STAT 31:free_chunks 3118 >> STAT 31:free_chunks_end 0 >> STAT 32:chunk_size 344 >> STAT 32:total_chunks 3048 >> STAT 32:free_chunks 3043 >> STAT 32:free_chunks_end 0 >> STAT 33:chunk_size 352 >> STAT 33:total_chunks 2978 >> STAT 33:free_chunks 2954 >> STAT 33:free_chunks_end 0 >> STAT 34:chunk_size 360 >> STAT 34:total_chunks 2912 >> STAT 34:free_chunks 2903 >> STAT 34:free_chunks_end 0 >> STAT 35:chunk_size 368 >> STAT 35:total_chunks 2849 >> STAT 35:free_chunks 2828 >> STAT 35:free_chunks_end 0 >> STAT 36:chunk_size 376 >> STAT 36:total_chunks 2788 >> STAT 36:free_chunks 2766 >> STAT 36:free_chunks_end 0 >> STAT 37:chunk_size 384 >> STAT 37:total_chunks 2730 >> STAT 37:free_chunks 2684 >> STAT 37:free_chunks_end 0 >> STAT 38:chunk_size 392 >> STAT 38:total_chunks 2674 >> STAT 38:free_chunks 2621 >> STAT 38:free_chunks_end 0 >> STAT 39:chunk_size 400 >> STAT 39:total_chunks 2621 >> STAT 39:free_chunks 2564 >> STAT 39:free_chunks_end 0 >> STAT 40:chunk_size 408 >> STAT 40:total_chunks 2570 >> STAT 40:free_chunks 2527 >> STAT 40:free_chunks_end 0 >> STAT 41:chunk_size 416 >> STAT 41:total_chunks 2520 >> STAT 41:free_chunks 2216 >> STAT 41:free_chunks_end 0 >> STAT 42:chunk_size 424 >> STAT 42:total_chunks 2473 >> STAT 42:free_chunks 2256 >> STAT 42:free_chunks_end 0 >> STAT 43:chunk_size 432 >> STAT 43:total_chunks 2427 >> STAT 43:free_chunks 2299 >> STAT 43:free_chunks_end 0 >> STAT 44:chunk_size 440 >> STAT 44:total_chunks 2383 >> STAT 44:free_chunks 1898 >> STAT 44:free_chunks_end 0 >> STAT 45:chunk_size 448 >> STAT 45:total_chunks 2340 >> STAT 45:free_chunks 1962 >> STAT 45:free_chunks_end 0 >> STAT 46:chunk_size 456 >> STAT 46:total_chunks 2299 >> STAT 46:free_chunks 2192 >> STAT 46:free_chunks_end 0 >> STAT 47:chunk_size 472 >> STAT 47:total_chunks 2221 >> STAT 47:free_chunks 2061 >> STAT 47:free_chunks_end 0 >> STAT 48:chunk_size 488 >> STAT 48:total_chunks 2148 >> STAT 48:free_chunks 2047 >> STAT 48:free_chunks_end 0 >> STAT 49:chunk_size 504 >> STAT 49:total_chunks 2080 >> STAT 49:free_chunks 1955 >> STAT 49:free_chunks_end 0 >> STAT 50:chunk_size 520 >> STAT 50:total_chunks 2016 >> STAT 50:free_chunks 1788 >> STAT 50:free_chunks_end 0 >> STAT 51:chunk_size 536 >> STAT 51:total_chunks 1956 >> STAT 51:free_chunks 1870 >> STAT 51:free_chunks_end 0 >> STAT 52:chunk_size 552 >> STAT 52:total_chunks 1899 >> STAT 52:free_chunks 1829 >> STAT 52:free_chunks_end 0 >> STAT 53:chunk_size 568 >> STAT 53:total_chunks 1846 >> STAT 53:free_chunks 1762 >> STAT 53:free_chunks_end 0 >> STAT 54:chunk_size 584 >> STAT 54:total_chunks 1795 >> STAT 54:free_chunks 1613 >> STAT 54:free_chunks_end 0 >> STAT 55:chunk_size 600 >> STAT 55:total_chunks 1747 >> STAT 55:free_chunks 1446 >> STAT 55:free_chunks_end 0 >> STAT 56:chunk_size 616 >> STAT 56:total_chunks 1702 >> STAT 56:free_chunks 1358 >> STAT 56:free_chunks_end 0 >> STAT 57:chunk_size 632 >> STAT 57:total_chunks 1659 >> STAT 57:free_chunks 1497 >> STAT 57:free_chunks_end 0 >> STAT 58:chunk_size 648 >> STAT 58:total_chunks 1618 >> STAT 58:free_chunks 1398 >> STAT 58:free_chunks_end 0 >> STAT 59:chunk_size 664 >> STAT 59:total_chunks 3158 >> STAT 59:free_chunks 1784 >> STAT 59:free_chunks_end 0 >> STAT 60:chunk_size 680 >> STAT 60:total_chunks 1542 >> STAT 60:free_chunks 1301 >> STAT 60:free_chunks_end 0 >> STAT 61:chunk_size 696 >> STAT 61:total_chunks 3012 >> STAT 61:free_chunks 302 >> STAT 61:free_chunks_end 0 >> STAT 62:chunk_size 712 >> STAT 62:total_chunks 4416 >> STAT 62:free_chunks 631 >> STAT 62:free_chunks_end 0 >> STAT 63:chunk_size 524288 >> STAT 63:total_chunks 26108 >> STAT 63:free_chunks 0 >> STAT 63:free_chunks_end 0 >> >> -- >> >> --- >> You received this message because you are subscribed to the Google Groups >> "memcached" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to >> [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/memcached/927615f7-187d-4c8f-9e08-f1f341b9a04an%40googlegroups.com. >> >> > > -- > > --- > You received this message because you are subscribed to the Google Groups > "memcached" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/memcached/alpine.DEB.2.22.394.2011121424300.2800104%40dskull. -- --- You received this message because you are subscribed to the Google Groups "memcached" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/memcached/76D01DF5-D89D-4CF1-B786-3F1B8FA9B2A0%40gmail.com.
